3d printing using rotational components and improved light sources

ABSTRACT

Methods, devices and systems for efficient 3D printing using a single compact device are set forth. Some embodiments utilize a circular-shaped build area revolving symmetrically around a single center point utilizing a continuous helical printing process. Laser diodes or vertical-cavity surface-emitting lasers (VCSELs) are utilized as an energy source for curing the print material. The VCSELs can be integrated with the print head and can form an array which can be staggered or linear. In some embodiments, the VCSELs (and the corresponding print head) can be connected to a rotating platform, which can rotate independently from the revolving build area. In some embodiments, a thermoelectric cooler and/or a fluid cooler can provide cooling to the VCSELS.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Divisional of U.S. patent application Ser. No.15/877,314 filed Jan. 22, 2018, which claims priority from USProvisional Application Ser. No. 62/448,905 filed Jan. 20, 2017 which isalso a continuation-in-part of U.S. Ser. No. 15/088,365, filed Apr. 1,2016, now U.S. Pat. No. 9,937,665, which is a divisional of U.S. patentapplication Ser. No. 14/207,353, filed Mar. 12, 2014, now U.S. Pat. No.9,321,215, which claims the benefit of U.S. Provisional Application Ser.No. 61/778,285, filed on Mar. 12, 2013. Each of these applications arehereby incorporated herein in their entirety by reference.

BACKGROUND OF THE INVENTION Field of the Invention

Described herein are methods, procedures and devices for formingthree-dimensional (3D) objects from a wide variety of media, such as apolymeric, biological or metallic materials. The methods, procedures anddevices are programmed to produce desired three dimensional (3D)structures using polymerization, crosslinking, curing, sintering,melting or solidification and similar techniques in a mannerconstituting improvements over conventional stereolithographic,photocurable, or other 3D object forming techniques.

Description of the Related Art

In recent years, 3D printing has been demonstrated to be an effectivetechnique for accurately forming 3D objects, such as for the purpose ofprototyping and manufacture. In its most general sense, 3D printingtypically utilizes a 3D scanner and/or computer software to generate animage map of a desired object. That image map is then translated into agrid-like structure such that a fabrication device can deposit aflowable material, such as a plastic, polymer, biomaterial or resin, viaan additive process, which is simultaneously solidified creating a 3Dobject. Various existing 3D printing methodologies which provide uniqueadvantages and also each have their own disadvantages.

One such methodology is stereolithography, credited as being developedby Charles W. Hull and set forth, for example, in U.S. Pat. No.4,575,330. Stereolithography aims to create three-dimensional objectsbased on the successive linear formation of layers of a fluid-likemedium adjacent to previously formed layers of medium and the selectivesolidification of those layers according to cross-sectional datarepresenting successive slices of the desired three-dimensional objectin order to form solid layers. Stereolithography technology uses aliquid medium that is typically a melted thermoplastic or a photopolymerwhich is selectively solidified. The thermoplastic solidifies byexposure to a lower temperature; the photopolymer is solidified byexposing it to radiation usually in the UV or visible wavelengthscausing the polymer to crosslink or cure. Typical methods for directingthis radiation onto photocurable materials include motor controlledscanning mirrors, mask systems or lasers wherein the smallest physicalresolution is the size of the laser beam or, within the mask, the sizeof a pixel.

Stereolithography-based machines solidifying photopolymer-based resinstypically utilize a singular, focused laser point which is scanned inthe X-Y plane using a physical gantry system or is otherwise directed byelectromechanically-driven highly reflective surfaces such asgalvanometers or rotating polygon mirrors. Because of this, print speedis inversely proportional to both layer density and layer volume.

A method of using the “singular point” type of stereolithography tosolidify photopolymers includes utilizing a laser and controllablemirror configuration is described in U.S. Pat. No. 4,575,330 to Hull.The process utilizes incrementally submerging a build-platform in a vatof photocurable material, wherein a layer of material that covers thebuild platform is solidified via targeted radiation from a laser usingtwo controllable mirrors which direct the radiation in a x/y plane alongthe surface of the material. Areas are selectively solidifiedcorresponding to cross-sectional data represented in a cross sectionalbitmap image of a slice of a virtual three-dimensional modelrepresenting an object. Lines are traced over the liquid surface tosolidify the photocurable material. The process is repeated multipletimes by lowering the build platform into the vat of material by anamount correlating to the next desired layer height. After new materialis deposited over the construction area, the process of solidificationrepeats to form the individual stacked layers to form a threedimensional object.

Another method, which utilizes a “plane exposure” typestereolithography, is the use of a Digital Micromirror Device(DMD)-based variation on the stereolithography process. These variationsprovide significant improvements in print speed and create a constantbuild time independent of layer density for a given layer volume,because DMD arrays can expose and direct entire planes of focused lightat once rather than a singular point which must be scanned to create alayer. A typical 720×480 DMD array can expose 345,600 individual“pockets” of solidified resin, also known as voxels, all at once in asingle layer exposure. Typical layer exposure times can range from0.2-10+ seconds, depending on a variety of factors. DMD-based processescan work very well for small print sizes, but once a critical layer areais surpassed, the suction force generated by layer-peeling mechanismwill inhibit buildup of the 3D object.

There are several limitations to the above processes. For example,resolution is proportional to the focusable point size of the laser; ifit is desired to increase the resolution, a smaller point size must beused. This has the consequence of increasing the total amount of linesto be traced in a given area, resulting in longer construction times.Additionally, the process of submerging a platform in a vat of materialis both limiting to the functional size of the object that can becreated and also requires exposure of large volumes of photocurablematerials to construct the 3D object.

Furthermore, the above method of subjecting a fluid surface to radiationposes its own set of issues with regards to consistent layer heights anderrors that can be caused from disturbances to the liquid surface. Thesedisturbances can result from both internal and external sources ofvibration. The layer height, and therefore the vertical resolution ofthe object, is also dependent on the viscosity and surface tension ofthe material used. This limits the vertical resolution that isattainable with a given range of materials.

Recently, an inverted sterolithographic process has been developed thatintroduces the additional factor of surface adhesion resulting from anewly solidified layer adhering to the bottom of a vat. This adhesionforce increases as a function of the size of the solidified layer.However, before the construction process can resume, the adhesion forcemust be removed and the build platform raised to allow new material tobe placed prior to the solidification of the next additional layers ofmaterial, for example, via use of prying, tilting, peeling and sliding.

These processes for removal of the adhesion force place the vat, thebuild platform, the raising element for the build platform and the newlysolidified geometries of the printed object under high stress loads thatcan decrease the functional life of the machine and its components, aswell as causing deformations and delamination of the object beingconstructed. A method to reduce this surface adhesion in large areasolidification is described in European patent application EP 2419258A2, where a single layer is broken into sub component images that aresolidified and separated individually. This method, however, doubles theconstruction time and increases the chance for product failure due todelamination caused by increasing the amount of unsupported areas to besolidified.

Common areas where all rapid manufacturing systems can be improved uponcomprise increasing resolution, enhancing scalability of constructibleparts, increasing the ability to construct difficult geometries, such ashollow cavities and overhangs, and increasing the ability to constructand preserve small and fragile geometries, such as those having littlesurrounding support. Time to construct individual layers and totalconstruction time are other important factors relating to the efficiencyof the construction process of every system each of which has to its ownset of unique limiting factors that dictate how long it will take toconstruct of a given object. Efficient methods and devices that addressthese conventional inefficiencies while utilizing a single compactdevice is therefore needed. Additionally, conventional light sourcesutilized in 3D printers have their own limitations and improved lightsources allowing for faster cure times is also desirable.

SUMMARY

Described herein are methods, devices and systems for efficient 3Dprinting that address inefficiencies and deficiencies of currentlyexisting 3D printing systems utilizing a single device. For ease ofexplanation and to provide an efficient nomenclature, the formation of3D structures using the new techniques, procedures and devices set forthand incorporating features of the present invention are referred to asheliolithography.

Heliolithography provides solutions to the above mentioned inherentproblems associated with traditional prototyping techniques. It allows3-dimensional solid physical products to be made directly fromcomputer-driven data and reproduced with very high and accurate levelsof detail, in a short time using a completely automated process. Certainaspects of Heliolithography are similar to stereolithography. BothHeliolithography-based and stereolithography-based processes can utilizea variety of materials as their base material, and these materials aresolidified into physical parts through various solidificationtechniques, such as a free radical polymerization of photopolymers uponexposure to a precisely directed and focused actinic photon source ofsufficient energy density. However, there are several key differencesbetween heliolithography and stereolithography-based printing processes.

Heliolithography utilizes the best of “singular point” and “planeexposure” concepts discussed above to continuously solidify the buildingmaterial, such as a photopolymer material, in thin lines by a spiralbuildup. When these lines are oriented as radii in a build area, forexample, in a circular-shaped build area revolving symmetrically arounda single center point, then a continuous printing process can beperformed in a helical fashion. The build platform (upon whichsolidified material is deposited to form the physical object) in oneembodiment is continually rotated and simultaneously raised in a verygradual manner while the material to be solidified, such as aphotopolymer is deposited as a liquid in a thin line on a transparentplatform. A stationary line of focused actinic radiation delivered froma position below the platform is directed into the liquid photopolymerto produce a single continuous “layer” of the now solidified materialdeposited and bonded to adjacent previously or simultaneously depositedmaterial in a helical fashion. Alternatively, heliography can also beimplemented by slowly raising the build platform without rotation whilea line of focused radiation “spins” beneath in a programmed manner,curing liquid photopolymer continuously. In a further embodiment, theplatform can be periodically or continuously rotated and at the sametime the actinic light can be periodically or continuously repositionduring the buildup and curing process.

Methods and systems incorporating features of the present invention seekto solve the issue of having both simultaneously high constructionresolutions while still preserving the ability to print large structuralobjects in a faster more economical way than can be achieved by theprior art. Such systems can utilize a continuous method for depositingand solidifying materials, for example, photocurable materials, in arotational manner that results in a spiral build-up of material.

In some embodiments of an apparatus incorporating features of thepresent invention, a rotating build platform with an elevation that canbe controlled along a Z-axis is utilized. This build platform is loweredonto at least one solidification area which comprises at least onematerial dispenser, at least one transparent substrate, for example,from which a material flows and is held against the build platformduring solidification, at least one drainage system to remove unusedmaterial and at least one excess material stripper for collecting andremoval and recycling of unsolidified materials. In aphotopolymerization process, electromagnetic radiation emitted from asource below the transparent substrate, is directed onto thephotocurable construction material in specifically targeted regions thatcoincide with point data derived from a three-dimensional object that isstored in the machines memory system.

In the use of photopolymers, both construction materials and irradiationsources are selected to provide a near instantaneous cure of theconstruction material. The solidified material adheres to the rotatingbuild platform, resulting in the continuous or semi-continuous spiralbuild-up of material to construct an object substantially similar inappearance to a desired three-dimensional object. In utilizing theseprocesses incorporating features of the present invention, verticalresolution of a constructible object can correspond to the layer heightor layer pitch angle of a continuous spiral layer of material and can becontrolled by altering the relative distance at which the inverted buildplatform is suspended above the photocurable material that is held on atransparent substrate.

In some embodiments, Vertical-cavity surface-emitting lasers (VCSELs)are utilized as highly efficient light sources. These VCSELs can beincorporated into a material dispensing component, such as a print head,and can be configured with rotational components to allow for rotationof the VCSEL arrays to customize curing. In some embodiments,thermoelectric coolers (TAC) and/or fluid-based coolers can be utilizedwith the VCSELs to provide cooling.

In one embodiment, a device for three-dimensional (3D) printing ofstructures in a vertical orientation can comprise a construction areaand a material dispenser with a flowable build material in the materialdispenser. The material dispenser can be positioned to deliver theflowable material onto an exposure zone of an upper surface of theconstruction area. The device can also comprise one or morevertical-cavity surface-emitting laser (VCSEL) chips on or adjacent thematerial dispenser, the VCSEL chips positioned to deliver radiation tosolidify the flowable material located on the exposure zone.

In another embodiment, a device for three-dimensional (3D) printing ofstructures in a vertical orientation can comprise a construction frame,a material dispenser with a flowable build material in the materialdispenser, and a construction area and a separate build platform, bothpositioned horizontally within the construction frame and configured forinverted build of a solidified 3D structure there between. The buildplatform can be moveable vertically within and configured to rotatewithin the construction frame and the material dispenser can bepositioned to deliver the flowable material onto an exposure zone of anupper surface of the construction area. The device can also comprise oneor more vertical-cavity surface-emitting laser (VCSEL) chips positionedto deliver radiation to selectively solidify the flowable materiallocated on the exposure zone and the build platform can be configured toreceive and retain the build material delivered on to the upper surfaceof the construction area as the build material solidifies and to movevertically upward and to rotate within the construction frame.

In yet another embodiment, a device for three-dimensional (3D) printingof structures in a vertical orientation can comprise a constructionframe, a material dispenser with a flowable build material in thematerial dispenser, and a construction area and a separate buildplatform, both positioned horizontally within the construction frame andconfigured for inverted build of a solidified 3D structure therebetween. The build platform can be moveable vertically within andconfigured to rotate within the construction frame and the materialdispenser can be positioned to deliver the flowable material onto anexposure zone of an upper surface of the construction area. The devicecan also comprise one or more vertical-cavity surface-emitting laser(VCSEL) chips positioned to deliver radiation to solidify the flowablematerial located on the exposure zone, wherein the material dispenser ison a rotary table configured to rotate in relation to a fixed base andthe build platform can be configured to receive and retain solidifyingbuild material delivered on to the upper surface of the constructionarea and to move vertically upward and to rotate within the constructionframe.

These and other further embodiments, features and advantages of theinvention would be apparent to those skilled in the art based on thefollowing detailed description, taken together with the accompanyingdrawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional exploded view of a 3D printer deviceincorporating features of the present invention;

FIG. 2 is a front perspective view of the 3D printing device of FIG. 1incorporating features of the present invention.

FIG. 3 is a cross-sectional exploded view of components of a 3D printerdevice incorporating features of the present invention;

FIG. 4 is a perspective view of an imaging component of a 3D printerincorporating features of the present invention;

FIG. 5 is a perspective view of a z-axis elevator stage of a 3D printerincorporating features of the present invention;

FIG. 6 is a perspective view of a build platform attachment plate for a3D printer incorporating features of the present invention;

FIG. 7 is a perspective view of a removable build platform insert for a3D printer incorporating features of the present invention;

FIG. 8 is a bottom view of a removable build platform insert for a 3Dprinter incorporating features of the present invention;

FIG. 9 is a top view of a view of an expanded solidification area/vatfor a 3D printer incorporating features of the present invention;

FIG. 10 is a partial internal perspective view of a base materialstorage and construction area of a 3D printer incorporating features ofthe present invention;

FIG. 11 is a perspective view of a complete solidification area of a 3Dprinter incorporating features of the present invention;

FIG. 12A depicts a single item being constructed radiating from thecenter of the build chamber floor of a 3D printer componentincorporating features of the present invention;

FIG. 12B depicts multiple items under construction radiating from thecenter of the build chamber floor of a 3D printer incorporating featuresof the present invention;

FIG. 13A is a side view of a continuous spiral layer constructionutilizing a single construction buildup area of a 3D printerincorporating features of the present invention;

FIG. 13B is a side view a continuous spiral layer construction builduputilizing multiple construction areas of a 3D printer incorporatingfeatures of the present invention;

FIG. 14 is a perspective view of a radiation source for a 3D printercomponent incorporating features of the present invention;

FIG. 15 is a perspective view of an alternative radiation source for a3D printer incorporating features of the present invention;

FIG. 16 is an expanded perspective view of another radiation source fora 3D printer incorporating features of the present invention;

FIG. 17 is a perspective view of a fourth radiation source for a 3Dprinter incorporating features of the present invention;

FIG. 18 is a perspective view of a fifth radiation source for a 3Dprinter incorporating features of the present invention;

FIG. 19 is a process flow diagram for a specific embodiment for aproduct buildup using the 3D printer device shown and described herein;

FIG. 20 is a process flow diagram for a specific embodiment for aproduct buildup using the 3D printer device shown and described herein;

FIG. 21 is a process flow diagram for a specific embodiment for aproduct buildup using the 3D printer device shown and described herein;

FIG. 22 is a side view of the 3D printer device of FIG. 1, with a 3Dstructure in the process of being printed;

FIG. 23A shows a front sectional view of a first VCSEL chipconfiguration embodiment incorporating features of the presentinvention;

FIG. 23B shows a front sectional view of a second VCSEL chipconfiguration embodiment incorporating features of the presentinvention;

FIG. 24A shows a front sectional view of a third VCSEL chipconfiguration embodiment incorporating features of the presentinvention;

FIG. 24B shows a front sectional view of a fourth VCSEL chipconfiguration embodiment incorporating features of the presentinvention;

FIG. 25 shows a front perspective view of an embodiment of a print headwith an integrated VCSEL array incorporating features of the presentinvention;

FIG. 26 shows the print head of FIG. 25 incorporated with rotationalcomponents to form an embodiment of a rotatable print head platformstructure incorporating features of the present invention;

FIG. 27 shows a side view of the rotatable print head platform structureof FIG. 26;

FIG. 28 shows a top, front, perspective view an variant embodiment of aVCSEL-based light source incorporating features of the presentinvention; and

FIG. 29 shows a schematic diagram of an example operationalconfiguration for a VCSEL light source printing system incorporatingfeatures of the present invention.

DETAILED DESCRIPTION

The present disclosure sets forth methods and devices for efficient 3Dprinting that address conventional inefficiencies and deficiencies whileutilizing a single compact device. As illustrative of such methods and3D production devices, the dispensing of a photocurable substance ontotransparent substrate, the selective curing and solidified of suchmaterials and the retrieval of the solidified product is described.However, one skilled in the art, based on the teachings herein, willrecognize that the apparatus and techniques described herein are notlimited to the use of photopolymers along with the irradiation sourcessuitable to effect solidification, but can be readily adaptable to abroad range of flowable materials that can be rapidly solidified for thecontinuous formation of solid, three dimensional objects.

Throughout this disclosure, the preferred embodiments herein andexamples illustrated are provided as exemplars, rather than aslimitations on the scope of the present disclosure. As used herein, theterms “invention,” “method,” “system,” “present method,” “presentsystem” or “present invention” refers to any one of the embodimentsincorporating features of the invention described herein, and anyequivalents. Furthermore, reference to various feature(s) of the“invention,” “method,” “system,” “present method,” “present system,” or“present invention” throughout this document does not mean that allclaimed embodiments or methods must include the referenced feature(s).

It is also understood that when an element or feature is referred to asbeing “on” or “adjacent” another element or feature, it can be directlyon or adjacent the other element or feature or intervening elements orfeatures that may also be present. Furthermore, relative terms such as“outer”, “above”, “lower”, “below”, and similar terms, may be usedherein to describe a relationship of one feature to another. It isunderstood that these terms are intended to encompass differentorientations in addition to the orientation depicted in the figures.

Although the terms first, second, etc. may be used herein to describevarious elements or components, these elements or components should notbe limited by these terms. These terms are only used to distinguish oneelement or component from another element or component. Thus, a firstelement or component discussed below could be termed a second element orcomponent without departing from the teachings of the present invention.As used herein, the term “and/or” includes any and all combinations ofone or more of the associated list items.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a,” “an,” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. For example, when the present specification refers to “a”source of radiation or “a” material it is understood that this language,in the first instance, encompasses a single source or a plurality orarray of radiation sources and, in the second instance, a single ormultiple sources of materials. It will be further understood that theterms “comprises,” “comprising,” “includes” and/or “including when usedherein, specify the presence of stated features, integers, steps,operations, elements, and/or components, but do not preclude thepresence or addition of one or more other features, integers, steps,operations, elements, components, and/or groups thereof.

It should be further recognized that reference to “solid” 3D structuresrefers to the materials of construction becoming solid and that the 3Dproduct produced is not necessarily a solid structure and may includeproducts with unfilled or hollow spaces therein or, if intended, anopen, porous or lattice-like structure and may in fact include spacestherein enclosing a liquid or non-solid filling material.

For the purpose of describing the construction procedure, the term“inverted” or “inverted build” refers to the method and procedure ofbuilding a 3D structure which is suspended below a horizontal assembledbuild structure 16, 18 with a portion sometimes referred to as the“base” of the 3D structure attached to the build platform insert 18. Theassembled build structure 16, 18 rises vertically from and above theconstruction/solidification area 20, as it prints a 3D structure 780such as shown in FIG. 22.

In some embodiments, the basic essential functionality of theHeliolithography process can be carried out through the use of 3D modelsoftware files, which produces an image map that is sectionalized into aspiral or helical structures using computer assisted drawing (CAD)-typecomputer programs. The spiral structure can be converted into segmentedimages or bit data corresponding to points along the surface areas ofthe intended printed object that are to be solidified by thecontrollable projection of radiation onto exposed areas to selectivelysolidify the materials of construction.

The solidification method can utilize any build material capable ofchanging from a liquid or flowable state to a solid in response to astimulus. For example, solidification can be the result of providing aradiative source which has the appropriate physical characteristics tocure or react the irradiated reactive liquid photopolymer materialpositioned on the rotating build platform. In some embodiments, thebuild material comprises a photopolymer solution containing at least onephotoinitator. The photoinitator absorbs radiation at specificwavelengths producing free radicals which cause the rapid polymerizationin the localized irradiated regions. Representative chemistries that canbe used can comprise unsaturated polyesters, styrene-Polyenes,Thiols-Acrylates, and methacrylates-Cycloaliphatic epoxides.Alternatively, a second reactive material can be dispensed to cause acrosslinking of a primary polymer. Further, thermoplastics can be heatedto liquefy and then rapidly cooled to solidify. As a still furtheralternative powdered metals or thermoplastics can be dispensed and “spotwelded” use a heat source or laser beam.

A typical formulation for a photoreactive material used in such aprocess comprises one or more monomers (molecules of low weight thatprovide the specific desired properties and adhesion), Oligomers (mediumlength polymer chains that contribute additional properties such asincreased tensile strength, stiffness, and elongation), photoinitiators(light sensitive materials that trigger free radical production toinitiate the polymerization process), and additives such as fillers,pigments, dyes, adhesion promoters, abrasion resistant materials, UVlight stabilizers and chemical stabilizers.

One example of a photopolymer formulation that can be used in theprocess described comprises a solution of monomer such as 1,6-Hexanediol(HOCH₂(CH₂)4CH₂OH) and Polyethylene Glycol Diacrylate(C₃H₃O).(C₂H₄O)_(n).(C₃H₃O₂) with one or more photoinitators,phenylbis(2,4,6-trimethylbenzoyl)-phosphine oxide [CH₃)3C₆H₂CO]2P(O)C₆H₅and Diphenyl(2,4,6 trimethyl benzoyl) phosphine oxide(CH₃)3C₆H₂COP(O)(C₆H₅)₂ at concentrations between 2 and 8 percent byweight.

FIGS. 1-2 show a sectional and front perspective views respectively, ofsome of the major functional components of an example 3D printer 10incorporating features of the present invention. The 3D printer 10comprises an imaging unit 12, a z-axis elevator stage 14, also referredto as the construction frame, a build platform 16, and a build platforminsert 18 which is configured to fit together with the build platform16, to provide an assembled build platform (as shown in FIG. 2).Although the present disclosure sets forth a configuration utilizingboth a build platform 16 and a build platform insert 18, it isunderstood that the use of the methods and devices incorporatingfeatures of the present invention can utilize the build platform 16alone without the build platform insert 18. Below the assembled buildplatform 16, is a construction/solidification area 20, a materialstorage area 22, a material cartridge/reservoir 24, electroniccomponents 26, and a solidification mechanism 28. These components andtheir various sub components are discussed in greater detail throughoutthe present disclosure.

With reference to FIGS. 1 and 2, a 3D file (corresponding to a desired3D object to be produced (the “print task”)) is loaded into the memoryof a print processor 100, which is configured to operate in conjunctionwith a CPU and solid state memory storage, to control the 3D printer 10.This print task can be transferred through the CPU and into solid statestorage in a variety of ways know in the art. For example, it can betransferred from a remote server or program using internet protocol(through its Ethernet or WiFi connection 102), or it can be loadedmanually by the user using a control interface 104 and/or universalserial bus (USB) data transfer ports. Control interface 104 can be anycontrol interface known in the art. In the embodiment shown, controlinterface 104 is a touch screen interface, such as an LCD touch screeninterface. The data can be uploaded to the apparatus which performsself-tests and priming functions to ready the machine for printing.Motor drivers 108, work in conjunction with the print processor byreceiving low-voltage signals from the print processor 100 andgenerating controlled current signals needed to properly drive thevarious motors used throughout the printer. Other electronics within theelectronics component assembly 26 of the 3D printer 10 include a powersupply 112, which can transform voltage input to provide regulated powerto all the components of the electronic component assembly 26. It isunderstood that while the power supply 112 is depicted as comprising anoutlet, any suitable power supply know in the art, for example, battery-or generator-based power supplies, are within the scope of the presentdisclosure.

The printer comprises a build platform 16 and a construction area 20.Build platform 16 can be permanently installed or replaceable, e.g.being removable connected to z-axis elevator stage 14. The buildplatform 16 can be rotatable clockwise and/or counterclockwise orotherwise moveable in one or more directions and can have a variety ofshapes including any regular or irregular polygon or can be circular orsubstantially circular. The build platform 16 can be lowered towards thesolidification area 20 using z-axis stepper motors 114; a sensor 124 canbe used to determine when the desired layer-height of an object to beproduced has been reached. The printer will then begin the print cycleby first ensuring all moveable axes are in the correct startingposition. For the z-axis, the starting position is typically one layerheight above the cure zone (above the home position). However, it isunderstood that other starting positions can be designated as needed fora particular print task and/or as newer technology becomes available andis incorporated into devices and methods according to the presentinvention. For the rotation axis, the starting position is the same asthe home position.

The homing process, which establishes the ‘0’, or start position of eachaxis, uses sensors 124, such as hall effect sensors, in aclosed-feedback system to determine the hard limits of each axis. Halleffect sensors are known in the art and typically comprise a transducerthat varies its output voltage in response to a magnetic field. Hardlimits for each axis can be driven from a pair of linear sensors, suchas hall effect proximity sensors 124, positioned at each limit. Whenutilizing hall effect sensors, one or more small magnets 126 can beembedded in the moveable z-axis carriage 14. Because the sensors have alinear analog output directly proportional to magnetic flux, each sensorcan be calibrated with its own trigger voltage.

Once hard limits are determined, printer firmware maintains in itsmemory the current position of each axis relative to its home position.When the printer is powered on, it can be programmed to re-home eachaxis before accepting new print tasks, for example, to compensate forsituations wherein an axis has been moved while the printer was poweredoff. The current position of each axis can be stored as an integernumber of motor steps from zero. In these configurations, moving theaxis “up” will increase this internal counter, and moving the axisdownwards will decrease the counter.

Soft limits can also be put in place to configure the printer such thatthe printer will never allow a motor movement that will send the axisbelow the lowest position or past the maximum allowed value, which isspecific to each axis' length. If an axis is directed to exceed thesepreset limits the printer controller will halt the print task and issuean appropriate error message. Also, if there is ever a programming errorand the printer attempts to move past the soft limit, the hard limitsbuilt into each axis will halt the axis movement and the print taskbefore any damage to the printer occurs, requiring entry of anappropriate soft reset.

The material storage area 22 can hold a replaceable material cartridge24. The material cartridge contains electronically stored informationwhich can be read by the 3D printer 10 to determine the amount ofmaterial in the cartridge 24 and other specifics about the material inthe cartridge. An agitator mechanism, such as a magnetic stirring device230, as shown in FIG. 10, can also be included and be located below thecartridge 24 to ensure materials are uniformly mixed prior todispensing. One or more atmospheric control mechanisms 119, such as anelectronic heating mechanism and/or a fan and/or humidifying controlsystems can also be used to alter the temperature of constructionmaterial in the material cartridge 24 or control the exposure tomoisture if needed, for example, to reach a desired viscosity or reducedetrimental moisture prior to dispensing. A thermal sensor and/orhumidity sensor can also be used to monitor when a desired materialtemperature is reached or that no excess moisture is present.

Referring to FIG. 10 a material pump 115 can be used to movephotocurable build materials, such as liquid-state photocurablematerials, from the material reservoir 24 to a material depositor. Atleast a minimal amount of material needed for a proper thickness coatingon the build surface can then be dispensed. A material such asphotopolymer resin can be introduced to the print area by the printer'sinternal plumbing system, driven by a small pump. With reference to FIG.1, as resin is introduced, it flows down resin supply channels in aprint head and flows over the cure zone and into resin return channels117. Excess liquid resin is continuously pulled from the resin returnchannels 117, filtered and returned to the resin tank or discarded, ifappropriate.

The assembled build platform 16, 18 can then be rotated, which spreadsliquid resin over the solidification area, depositing and evenlyspreading the photopolymer to a desired layer thickness. In someembodiments, the desired thickness is between 0.001 and 0.1 mm inthickness. A secondary material dispenser can optionally be used toinfuse the primary material with additional additives, pigments, dyes,coloring agents into the primary photopolymer prior for curing. In analternative embodiment, the secondary material can be a materialreactive with the first material to effect solidification.

It is understood that while the embodiments described herein set forth arotatable build platform and stationary material dispensers andsolidification areas, the reverse configuration would also work and bewithin the scope of the present application, wherein material dispensersand solidification areas rotate under a stationary build platform. In analternative embodiment, the material dispenser, solidification and buildplatform can be simultaneously or alternatively moved in a programmedmanner.

Once a continuous resin flow is established, the assembled buildplatform 16, 18 begins to rotate before the solidification processbegins to establish a uniform flow of material across a materialspreader. The rotation of the assembled build platform 16, 18 isperformed with the use of a variable speed motor 136 that drives acentral shaft 137 with engaged 90 degree gears 138 that rotate both thescanner and assembled build platform 16, 18 that are suspended on one ormore bearings 142 connected to the z-stage 14. The build platform can beset to spin for set number of rotations, also known as the “spin-up”period. The rotation of the assembled build platform 16, 18 helps todraw new material over the cure zone and ensures that no air is trapped.Without pausing rotation, the printer begins the printing process byactivating the solidification mechanism to begin the photo-cure process.

Continued rotation of the build surface (or movement of the feedmechanisms or other components programmed to move) advances the printmaterials onto an across an exposure/cure zone 118, which is preferablyglass or another sturdy, transparent and preferably low adhesion medium.The exposure zone 118 can be treated with a non-stick and abrasionresistant coating, which prevents or retards cured material fromadhering to its surface. Selective solidification of the segment ofmaterial deposited between the build platform and the transparentconstruction surface, is carried out by one of a number of possiblecombinations of radiation sources and radiation directing mechanismsused to direct the radiation through the transparent substrate portionof the solidification area onto and into the liquid constructionmaterials. Material level sensors in the material cartridge 24 are alsoused to monitor material levels and are capable of pausing or slowing aprint cycle if material levels become critically low.

The data stored in the memory of the printer is transmitted to thesolidification mechanisms 28 in a programmed manner to selectivelyexpose portions of the photopolymers through the transparent substrate,solidified in a manner corresponding to the structural informationrelating to specific segments of the 3D model which is beingconstructed. The Heliolithography process, which appears to becontinuous can actually comprise many small cumulative “steps” for eachfull rotation of the build platform, pausing at each step for a smallamount of time, typically between 5-10 milliseconds required to allowthe polymerization reaction to progress past a critical “degree of cure”(i.e., a level of solidification) needed to sufficiently attach to thebuild platform insert 18 and firmly adjacent previously solidifiedportions of structure being formed. As an alternative the build platforminsert can comprise a removable retention means added to the lowersurface thereof which can be incorporated onto the first layers of theproduct being built so as to allow removable attachments of thatstructure, once completed, from the build platform insert. In someembodiments, referring to FIG. 8, the holes can be shaped to addalternative retention structures 770 such as inverted cones oradditional structures 770 can be added to provide further retention ofthe structure being built. Unsolidified material is simultaneouslyremoved and recycled back into the reservoir.

As the portion of the structure being built is sufficiently solidified,the rotating assembled build platform 16, 18 continuously removes thesolidified material from the exposure zone 118 and provides newconstruction material spreading across the construction area 20.Solidified material is also, at the same time, rotated towards arecycling area comprising a drain 132, such as an excess materialsstripper, that removes any unsolidified materials from the growingstructure which are then filtered and recycled back into theconstruction materials reservoir 24, and a further curing mechanism 133,if necessary.

As each additional step of the build process is reached, new informationis provided to the curing mechanism 133, so as to solidify the resinwhere and when needed. As the assembled build platform 16, 18 rotates,it is continually raised by the linear actuators in a ratio such thatthe assembled platform 16, 18 is raised one layer height for eachrevolution. In some embodiments, one layer height corresponds to thenumber of radii of an intended curing piece of the structure. Forexample, in embodiments utilizing one material while curing down thediameter (i.e. radii) a full layer would be cured during every 180degree rotation of the build platform. In some embodiments utilizingmultiple cure areas, but still utilizing a single material, a singlelayer can be cured faster with less rotation, for example, atapproximately 360 degrees/number of cure radii. The linear actuatorsinclude stepper motors 146 that are coupled via coupling devices 148 tofasteners, such as lead screws 150, so as to raise the z-stage which isconnected with fastener acceptor, such as a lead screw nut 152, whenrotated. Bearings 154 and linear guide rails 156 mounted in the z-stage14 stabilize this vertical movement.

This cycle is repeated until the spirally deposited and solidifiedmaterial is built up and the constructed three-dimensional objectsuspended below the assembled build platform 16, 18 but above theconstruction/solidification surface 20 is completed. This process isrepeated in a continuous fashion until, cumulatively, the total heightof the printed object has been reached. Once this is accomplished andthe cure mechanism has no remaining information in its input buffer, thecuring mechanism (the photon source) is shut off and the rotation of thebuild platform is stopped. The resin flow is shut off and all remainingliquid resin drains back into the material cartridge. The machineinitiates a motion sequence raising the build platform to its upper softlimit and brings the rotation of the platform to its homed ‘0’ position.

In addition to utilizing preexisting software print modules, methods anddevices incorporating features of the present invention can also utilizescanning and other imaging units. In some embodiments, objects can beplaced on a scanner platform 139 and the printer 10 can be instructed tobegin scanning. The z-stage 14 raises the object to an initial height tobegin a scan. A pattern imaging device 206, such as a projector, orlaser can be used to project a known geometric pattern on the surface ofthe object. A recording device 208 can then record the distortions tothis known geometric pattern as the scanner platform 139 rotates drivenby the same variable speed motor 136 and drive gears 138 as the buildplatform. The height of the object can be raised or lowered using thelinear actuators to perform subsequent passes to generate greatercoverage of the object geometry to include under cuts and over hangs.This information is then sent to the processor 100 and transmitted viaEthernet, WiFi or wired connection 102 to a computer or cloud system forthe reconstruction of the scanned object.

Many different solidification mechanisms can be utilized with methodsand devices according to the present disclosure. A solidificationmechanism 28 used in the device of FIG. 1 can include any radiationsource such as high power diodes 212, 214, with the radiation directedthrough correcting and focusing optics 222 and onto a motor controlledmirror scanning system 220 for directing the radiation through theexposure zone 118 of the cure zone. Other solidification mechanisms arediscussed further below.

FIG. 3 shows an exploded view of an imaging unit 12, a z-axis elevatorstage 14, a build platform 16, a build platform insert 18 which isconfigured to fit together with the build platform 16 to form anassembled build platform 16, 18 (as shown in FIG. 2), aconstruction/solidification area 20, a material storage area 22, and amaterial cartridge/reservoir 24. FIG. 3 shows these components alignedin correct configuration according to some embodiments incorporatingfeatures of the present invention, such as the embodiment 10 depicted inFIGS. 1-2 of the present application. FIG. 4 shows an enlarged view ofthe imaging unit 12, which comprises a pattern imaging device 206 and arecording device 208 as discussed above. The imaging unit 12 can beconnected to z-axis elevator stage 14 via bearings 154 as shown in FIG.1.

FIG. 5 shows a more detailed view of z-axis elevator stage 14, whichcomprises magnets 126, which can interact with hall effect sensors torelay the position of the z-axis stage 14, a variable speed motor 136that drives a central shaft 137 with engaged 90 degree gears 138, ascanner platform 139 and fastener acceptors 152. These components canfunction as set forth above.

FIG. 6 shows an enlarged view of the build platform 16. One aspect moreclearly shown in FIG. 6 is the insert accepting portion 224. FIG. 7shows the build platform insert 18 and the inset connecting portion 226.The insert accepting portion 224 of the build platform 16 as shown inFIG. 6 can be configured to interact or mate with the inset connectingportion 226 of build platform insert 18 shown in FIG. 7 such that thetwo components can be connected into an assembled build platform 16, 18(as shown in FIG. 2, for example). This allows the build platform insert18 to be readily removed and replaced in the device. FIG. 8 shows abottom view of the build platform insert 18 comprising arrays of holes228 allowing increased surface area for building materials. Theremovable build platform insert 18 or a removable attachment to thebuild platform insert 18 can be separated from the complete product orremain as a piece of the complete product.

FIG. 9 shows an enlarged view of the construction/solidification area20, comprising a primary material dispenser 180, a cure zone 118, resinreturn channels 117, a material spreader 182, and a curing mechanism133, such as an excess materials stripper, these components functioningas set forth above.

FIG. 10 shows an enlarged top perspective view of the material storagearea 22 and the material cartridge reservoir 24. Also shown in FIG. 10are the control interface 104, a material pump 115, resin returnchannels 117, an exposure/cure zone 118, which is a transparentsubstrate, an atmospheric control mechanisms 119, curing mechanisms 133,a coupling devices 148 attached to fasteners 150, linear guide rails 156within the coupling devices, a primary material dispenser 180, amaterial spreader 182, a secondary material dispenser 184 and a magneticstirring device 230. FIG. 10 also shows additive material cartridges 186which can be configured to feed secondary material through primarymaterial dispenser 180 and/or a secondary material dispenser 184.

FIG. 11 shows a condensed perspective view of a construction zone 720,comprising primary material dispenser 180, a material spreader 182, asecondary material dispenser 184, an exposure/cure zone 118, which is atransparent substrate, resin return channels 117 and curing mechanisms133. The same structures are shown in FIG. 12A which shows a singleconstruction zone 720 radiating from the center of the floor of thebuild chamber 21. FIG. 12A also shows an additive material cartridgestructure 186. FIG. 12B shows an alternate configuration, whereinmultiple construction zones 720 and additive material cartridgestructures 186 radiate from the center of the floor of the build chamber21.

For illustrative purposes, FIGS. 13A and 13B are side views of a spirallayer printing construction for a single construction area 231 and formultiple construction areas 232, respectively. The use of multipleconstruction areas further provides the benefits of simultaneous layercreation or the expanded ability for a greater range of constructionmaterial options wherein each construction area can dispense andsolidify a unique range of materials into a single layer. For depositinginto a single construction layer the subsequent heights of theconstruction substrates can also match the pitch of the spiral layer tobe created and insure consistent layer thickness at each constructionarea. However, this is not necessary to achieve the desired coloraccuracy. This process can also be utilized wherein the build platformis rotated but raised only after one complete rotation is accomplished.This is of particular value where multiple construction areas of thesame height are used. In such instance a consistent layer height foreach material segment can be efficiently achieved. In actual operationthe depicted expanded spiral can never occur as proper solidificationtechniques adhere and solidify together adjacent subsequent layers ofthe spiral laydown as they are formed.

Various solidification mechanisms and radiative sources can be utilizedwith devices and methods incorporating features of the presentinvention. FIG. 14 shows the solidification mechanism 28 of FIG. 1. Whena photopolymer is used solidification mechanisms 28 can include variousradiation sources such as high power diodes, LEDs or lasers 212, 214. Ina particular embodiment the radiation is directed through correcting andfocusing optics 222 and onto a controlled scanning mirror system 220adapted to scan the incident light such as by use of a motor drive fordirecting the radiation through the exposure zone 118. Thesolidification mechanisms 28 can further incorporate a DMD Chip Micromirror device (not shown).

FIG. 15 depicts a solidification mechanism 235 utilizing aMicroelectromechanical systems (MEMS) or light valve switches. Depictedare high power diodes 212, 214, similar to the diodes that can beutilized with solidification mechanisms 28 described above, coupled tolight/wave guides 236 in an optics system 238 for focusing onto a lightswitch 240 assembly. The light switch 240 is a mechanism allowingradiation to pass through at desired locations arranged in anoverlapping hexagonal grid system. Fans and heat sinks 242 and a TECtemperature control system 244 can also be utilized for temperaturecontrol.

FIG. 16 shows an alternative solidification mechanism comprising a boardradiation source 246 such as an ultra-high performance (UHP) MercuryVapor lamp 248. This mechanism uses a convex reflector 250 for focusingthe radiation from the source 246 towards a digital mask 252 such as aLCD screen. The digital mask controls radiation passing throughaccording to a pixel matrix programmed to block or transmit theradiation flowing there through.

FIG. 17 is a further alternative solidification mechanism using aradiation source 254 comprising a high power diode 246 and a motorcontrolled mirror, such as a polygonal multi-sided mirror 258. Themirror is rotated in relation to the diode, or vice versa, to scan theradiation in a linear direction corresponding to its angle of rotation.A 45 degree secondary mirror 260 is used to reflect the radiationtowards an exposure zone such as the transparent substrate of the curezone 118. This secondary mirror 260 can be motor controlled to provide asecond dimension of scanning. An optics system 262 is also used tocorrect for distortions and scanning angles. In some embodiments, anF-theta optic system is utilized.

FIG. 18 shows further alternative solidification mechanism 264comprising an array of individually addressable diodes 265 such as amicro-LED array 266, that can be used independently to control thesolidification of the construction material. An optic system 268 canalso be used to focus the radiation to a desired point size between 5and 50 nm.

A still further alternative can be to use one or more laser beams, whichmay or may not require focusing mirrors, as the laser beams can beindividually positioned or repositioned as necessary to deliver narrow,pin point beams of controlled frequency light to specific targetlocations.

With reference to FIG. 22 a specific product is constructed utilizingdevices incorporating features of the invention. Using the scanningtechniques described above, the dimensional features and surfacecharacteristics of a three dimensional object measuring about less thanabout 10.5 inches in diameter and less than about 9.25 inches tall werescanned and the scanned data relating thereto was stored in the memoryof a 3D build system such as shown in FIGS. 1-2. A photo photopolymer,preferably an acrylate methacrylate resin comprising 2-8% of acombination of diphenyl (2,4,6 trimethyl benzoyl) phosphine oxide,Thermoplastic Polyolefin (TPO), and/or Phenylbis(2,4,6-trimethylbenzoyl) phosphine oxide, was added to the materialstorage area 22. A light source suitable to effectively cure thephotopolymer within 3-10 cc/sec comprising an array of micro LED(365-385 nm) to provide irradiation of the polymer over at least about10.5″ width or diameter (approximately 200-300 watts/cm²). Additionallight sources, including light sources utilizing one or morevertical-cavity surface-emitting lasers (VCSELs), are discussed ingreater detail further herein.

The polymer was metered at a rate of about 3-10 cc per second which isdependent on the dimensions of the object being built distributed onto a12 inch diameter construction area (cure surface) with a transparentexposure zone, which can be a smaller portion of the construction area,for example, a 1 inch wide portion that is transparent to a certain typeof radiation, such as UV radiation, which can be made of glass. Thisexposure zone had been previously treated with a low adhesion materialsuch as Fluorinated ethylene propylene (FEP) and/orPolytetrafluoroethylene (PTFE), know commercially as Teflon®, to retardor prevent adhesion of the cured polymer to the cure surface. Theresultant liquid polymer film was about 20-100 microns thick. Therotation rate of the built platform is primarily dependent on size anddensity of the product being built and the solidification rate of thematerial of construction, which in turn is dependent on the intensityand frequency of the irradiation source. The platform was rotated at arate of 2-12 rpm.

The speed of construction can be enhanced by use of multiple cure areasand multiple feeds. However, construction of a structure is dependent onthe size of the structure and the thickness of build material that canbe cured per exposure. A general equation for estimating build speed isas follows:

${{Build}\mspace{14mu}{Speed}} = {\frac{1}{\left( {{RPM}*{Number}\mspace{14mu}{of}\mspace{14mu}{Radii}} \right)} \times \frac{{TOTAL}\mspace{14mu}{HEIGHT}}{{LAYER}\mspace{14mu}{HEIGHT}}}$

Accordingly, for a structure with an intended height of 9 inches (228.9millimeters) with a layer height of 50 microns (0.05 millimeters), arotation speed of 5 RPM and a single cure zone, a build time isestimated to be approximately 915.60 minutes, which is approximately15.26 hours ([⅕]*[228.9/0.05]). However, with four cure zones such asshown in FIG. 12B the build time is cut to 25% (approximately 3.8hours). Depending on the build material additional cure zones can beadded to further reduce the build time.

The method described herein of rotating the build platform allows for alarger surface area to be exposed to the electromagnetic radiation usedto solidify the deposited photocurable materials resulting inconstructing of objects that are larger than the physical dimensions ofindividual solidification areas, thus allowing the construction oflarger objects. By utilizing a small area for solidification, higherresolutions and power densities can be attained by concentrating thenumber of solidification points to a smaller and denser region, whichthrough rotation, can irradiate entire portions of the build area. Thisreduced solidification area also results in a greater concentration ofradiation to targeted areas which helps to provide a close toinstantaneous cure of construction materials, yielding fasterconstruction of an object.

The method of curing or otherwise solidifying material between a buildplatform and another substrate yields greater layer height uniformity,accuracy and consistency. This method also helps prevent errors duringlayer creation that can result from external factors such as vibrationthat might have otherwise disturbed materials that were not held inplace between two substrates. This translates to greater reliability ofthe machine with particular benefits in constructing small, ultra highresolution, components so that they can be prevented from being deformedor distorted by internal or external disturbances on the 3D builddevice.

The problem of part delamination seen in many prior 3D build systems canbe caused by forming successive individual layers of material which areinherently structurally weak along their horizontal axis's (i.e., wheresubsequent layers are in contact). The combined action of forcibly andrepeatedly separating the solidified material from a vat floor andinadequate adhesion between layers can result in one or more layersseparating causing a failed structure build. In particular, objects thatcontain dramatic changes in areas of increased solidification can resultin fracturing of structurally weak areas that or in highly dense regionsof solidified material due to the inability of the structures to provideadequate support and structural integrity and external forces applied toit during the construction process. Increasing the build area in theselocations can further exacerbate the problems described above and resultin greater risk for printed object fractures via delamination. Theprocess and devices described herein provide reduced surface adhesionbetween solidified materials and the transparent build and as a resultpreserve the integrity of delicate geometries that are constructed andenhance the ability to use speeds in the construction process.

Methods incorporating features of the present invention includingselectively solidifying the construction material in a relatively smallarea comparable to the total construction area serve to reduce adhesionforces by minimizing the physical area that generates the adhesion. Therotational motion of the build platform serves to continually removethis adhesion force as it forms preventing adhesion force accumulation.This allows for the construction of a large area with only a smallportion of the constructible area ever being subject to the adhesion ofmaterial to the substrate at any given time. The transparent substratebe composed of or being treated with non-stick materials, furtherreduces the effects of adhesion.

Methods which incorporate features of the present invention includerotating the build platform about and above the solidification areas,providing for an innovative method for separating cured materials from abuild substrate. The circular motion generated by the rotating buildplatform provides a superior separation method that reduces damage tonewly solidified material because less force is needed to separate orslide the solidified material off the transparent build substrate andless force is applied to the constructed part. This allows theconstruction of very delicate geometries that can be unsupported, small,tall, thin or isolated and that could otherwise have been damaged in theseparation processes of prior art 3D build systems. The method forcontinuous or semi continuous construction utilizing a rotatingmechanism for dispensing and solidifying of photocurable materialagainst a build platform that gradually moves upward along a z-axisresults in the creation of at least one continuous spiral or helicalshaped layer. This spiral buildup of material results in the formationof an objects with superior layer-to-layer strength characteristicswhich aides in diminishing the chance for part delamination and resultsin lower occurrences of failed structures.

The inverted construction process provides several benefits. In severalprior art systems an object is built on a platform with a first layer onthe platform and subsequent layers are added on top of the prior layers.While some prior systems may use an inverted build, in the presentinverted build system, a first layer is continuously applied to a buildplatform and solidified. However, the first layer is also continuouslyremoved as a solid layer from the build platform during the buildprocess and new material is fed between the first layer and the buildplatform so as to adhere to the rising prior layer while beingcontinuously removed from the build platform. It allows forsolidification of a large area with a relatively shallow layer ofmaterial needed, allowing for less material being used during theprocess compared to the amount of material needed to fill an entire vat.The vertical and inverted construction process utilizes gravity to drainexcess material from previously solidified regions. The ability to formhollow cavities within the structure is very beneficial with regards tomaterials savings, and producing of objects with internal geometries.The use of a material stripper and drain help to further remove excessmaterial for recycling, thus improving the economy of the machine andpreventing the unintentional curing of excess material which can allowproduction an object that more closely resembles an intended product andhas sharper details.

The method of utilizing rotational movement for construction, instead oflateral back and forth motion, as referred as oscillation, provides forincreased scalability of the machine. Unlike oscillation, rotationalelements that are in continuous motion in one direction do not havecompensate for momentum resulting from the oscillating movement.Therefore, a machine that utilizes the described rotational techniquecan comprise larger and heavier components that would otherwise havesignificant negative impact on the construction process and operationalspeed. In this rotational method of construction speed is independent ofconstruction volume. Increasing the size of the construction mechanismand the build platform will result in a greater possible build volume,translating to comparatively faster construction from a given volume ofmaterial.

Embodiments of the invention are described herein with reference todifferent views and schematic illustrations of idealized embodiments ofthe invention. As such, variations from the shapes of the illustrationsas a result, for example, of manufacturing techniques and/or tolerancesare expected. Embodiments of the invention should not be construed aslimited to the particular shapes of the regions illustrated herein butare contemplated to include deviations in shapes that result, forexample, from manufacturing.

While devices, systems and methods incorporating features of the presentinvention are primarily directed to stereolithographic processes usingliquid-based building materials. The techniques of the present inventioncan have application using other flowable materials and appropriatesolidification technologies such as selective laser sintering (SLS), forthe purposes of enhancing resolution, faster construction times,economic material use and the ability to form hollow cavities in aconstructed object that would otherwise be filled with excessconstruction materials. Such an embodiment can utilize heatedconstruction materials which are then solidified. The use of a laserdiode that emits radiation in the infrared spectrum a constructionsubstrate also transparent to infrared radiation. Thermal andatmospherically control over the material and build chamber 21 isdesirable for greater control over the reacting materials in theconstruction process.

Sintered materials such as metals or powdered polymers can be used withthe above process along with a heating and/or radiation source forthermal heating and/or fusing of material. Main differences from theabove recited processes can be the possible addition of an atmosphericcontrol system that would fill the build chamber 21 with an inert gaslike argon or nitrogen and a thermal control system like infraredheaters. Laser beams can be used to melt and fuse the constructionmaterial.

Flowable sinterable materials or additives can also be used as, or aspart of, the construction material. The sinterable materials can then bebound in place by the curing of surrounding photopolymers or the meltingor binding of a powdered polymers resulting in production of a “greenobject.” This green object then requires the additional steps forconverting the green object to create higher part densities, known aspost furnace processing which can include debinding which comprisesplacing the part in a furnace at a temperature that vaporizes orcarbonized the binding material and promotes a controlled shrinkage ornecking of the green build material to hold its shape while forming asolid structure.

Infiltration, which is a process for infusing the formed solid butporous part with another material, filling in the porous voids in thepart. This infused material can have a lower melting point then the mainconstruction material. An example of one such material suitable forinfiltration is copper. Molten copper can diffuse into iron powderparticles creating swelling. By controlling the copper concentration, itis possible to offset the natural shrinkage of iron during sintering tohelp preserve part dimensions of the green object. Such a process canalso be used to form structures from bio-compatible materials which canthen be infused with other biomaterials to form biologically compatibleimplant structures.

Consolidation is a process which can occur during sintering, results inthe product shrinking so as to increase the part density.

With the inclusion of a laser of sufficient power, direct thermalsintering of the construction materials or a concentration of additivescontained in a dispensed formulation whose components are capable offusion to each other and the build platform is possible. This embodimentneeds greater thermal control of the material and build chamber 21 aswell as a means for regulating the atmosphere which would utilizeblanketing of the solidification area with inert gases such as nitrogenand argon and a method for removing any gaseous byproducts.

Examples of sinterable additives are: 17-4 and 15-5 stainless steel,maraging steel, cobalt chromium, Inconel 625 and 718, titanium Ti6Alv4,titanium Ti64, Cobalt Chrome Alloy Co28Cr6Mo, Nickel Alloy In718Theoretically, almost any alloy metal can be used in this process.Sintering typically involves induced binding, liquid phase sinteringand/or full melting. These techniques are known in the art.

FIGS. 19-21 show a process flow diagram, which can incorporate computersoftware, for utilizing 3D printing devices incorporating features ofthe present invention. Regarding FIG. 19, which shows a user-initiatedprocess 800, the session is started in an initiation step 802, which caninclude the initiation of software, such as OM (an Omicron CompilerFile) software or other suitable software. A user can engage in andinitiate a series of interrelated user actions. For example, a use canactivate an import step 804, wherein the user imports 3D geometry, forexample, from existing data or from recently scanned data. From thisstep, the user can elect to initiate a save step 806, in which the usercan save the 3D geometry data, for example, an .OM software file.Alternatively, or in addition to initiating a save step 806, a user caninitiate a manual re-size/reposition step 808 of the imported 3Dgeometry data. The 3D geometry data can then be automaticallyre-sized/repositioned in an automated adjustment step 810.

At any point, an existing file, for example, an existing .OM file savedin the save step 806 or a manually and automatically adjusted file fromthe manual and automatic adjustment steps 808, 810 can be loaded intothe memory of a user interface in a load step 812. From the load step812, several additional steps can be initiated. For example, a user caninitiate a duplication step 814, wherein one or more aspects of the 3Dgeometry data can be duplicated. A user can then initiate an applicationstep 816, wherein a user can alter and/or apply colors and othermaterial options to the 3D geometric data. The user can then initiate aconnection step 818, wherein the user can locate a local 3D printer andconnect, after which the user can initiate a print step 820, wherein the3D object begins to print.

During the setup process and compiling the print instructions forprinting the 3D object in the print step 820, instructions can beprovided to produce a solid or a hollow structure and additional stepscan be initiated to further define the object. A user can initiate ahollowing step 822, whereby a hollow object is produced instead from,and instead of, an existing solid object. A user can then initiate ahollowness adjustment step 824, whereby the wall thickness of hollow orshelled products can be adjusted. An automated infill step 826 can alsobe initiated, wherein infill for hollow models is automaticallygenerated. Finally, a user can initiate a customization step 828,wherein additional customized print-specific settings are applied to the3D object.

It is understood that while the examples cited above specifically referto .OM files, other software file formats can be utilized. For example,users can import 3D models formatted as AMF, STL, PLY<OBJ, or any othersimilar file known in the art. Support for auto-detecting colors and/ormaterials can be included. Each piece of unique imported 3D geometrydata can be stored along with the transformation matrix (applied fromthe origin) and metadata describing color and material selections.

Referring now to FIG. 20, which shows a further process flow diagram 850incorporating features of the present invention, an automated printpreparation (scan) process 852 is initiated by the user or in responseto a stimulus, for example, the printer being powered on or receiving aconnection signal from a computer or other user interface. In a firststep 854, intelligent mesh consolidation of an object being reproducedtakes place. In some embodiments, an algorithm is utilized toconsolidate all meshes in preparation for slicing. This first step 854can be used in the production of separate combined meshes each organizedby color and material. In a second step 856, the algorithm can, ifnecessary, automatically generate and add any support structures neededfor each combined mesh. In a third step 858, radial slicing of the meshcan occur. In this step 858 one or more algorithms can radially slicethe input mesh and produce encoded vector data describing the intendedstructure to be printed in real-world dimensions utilizing real-worldunits. This data can be stored and later compiled to machine-specificinstructions. Layer height is taken into account at this stage and canbe pre-set as a constant value for the entire print or vary throughoutthe print.

In a fourth step 860, the print job is compiled by one or morealgorithms to produce a single compiled (machine-specific) print jobfile containing all the print information utilized by the printer. In afifth step 862, this compiled print job file, which can be machinespecific and can be in .OM format, is transferred to the printer.

Referring now to FIG. 21, which shows an example of a process flow 880after a step 882 wherein the print-job file is compiled and transferredto a printer (which can be a continuation of the fifth step 862 in FIG.20 or proceed directly from a loaded externally or independent providedprint file). In a first step 884, an algorithm translates vectorinstructions from real-world units into a binary arrangement (arrays ofindividual ones and zeroes) that is used by the printer. In a secondstep 886, the print processor of the printer streams data bits to thecuring mechanism at a hardware-synchronized rate that coincides with themotor/mirror movement. In a third step 888, the actual heliography(curing) process occurs, utilizing continuous computer-controlledselective solidification. In a fourth step 890, a completed physicalobject mirroring the virtual 3D geometry is produced.

The present disclosure will now set forth various configurationsutilizing VCSEL light sources, which have several distinct advantages.Various 3D printing techniques are based on photo-initiation fromdirect-emitted, single-transverse mode that is focused to a small spotof 1-100 microns diameter to locally start the polymerization process.The energy is absorbed by a photointiator, typically but not limited toan organic molecule that absorbs efficiently at the wavelength ofinterest to create free radicals, which then catalyzes the rest of thereaction—propagation steps, crosslinking and subsequent termination.Different photoinitiators may require different wavelengths ofexcitation for efficient initiation to take place. This requires aserial solidification process and limits the amount of energy that canbe delivered precisely.

3D printing techniques including polymerization of liquid pre-polymersystems, sintering of powder materials, powder w/curable binder, polyjettechnologies, etc have been around for several decades, reachinglimitations of scalability. Limiting factors for scaling include theamount of material that can be solidified at any given point in time,which is coupled to the amount of energy that can be delivered inprecise quantity, usually done with a point source that is scanned. Withthis approach, print speed is inversely proportional to complexitybecause the spot size must be scanned serially point-to-point to coverall areas of the current layer.

Some systems use Digital Micromirror Device (DMD) chips consisting ofrectilinear arrays of tiltable mirrors, to expose a plane of pixels atonce. This accomplishes parallelization of cure and the entire layer canbe exposed in the same amount of time regardless of the specific crosssection—however, the energy density delivered to the cure area is aninverse square function, with energy decreasing as the square root ofthe build area. In practicality, this combined with the power handlinglimitations of the DMD chip, limits the size of the cure area that canbe exposed in a single image without requiring excessively long layerexposure times.

In contrast, the disclosed VCSEL configurations accomplishes bothparallelization of cure and infinitely scalable energy input byutilizing arrays of semiconductor by utilizing VCSELs to preciselydirect energy into the cure area, pixel-for-voxel. These VCSEL arraysare built using standard semiconductor batch manufacturing andprocessing techniques, and represent significant advancements in lightengine scalability, reliability, and ease of processing, when comparedto conventional edge-emitting laser systems. Additionally, the light isdirectly coupled in preferably a 1:1 magnification ratio (or other) fromthe chip into the cure zone, and as a result does not require complexoptical systems to project light from a small source to a large area.The resulting system is extremely compact and optomechanicallysimplified.

Most solid-state lasers are edge-emitting structure variety, which arenot conducive to assembling large linear areas due to the correspondingdifficulties of cleaving and assembly. In contrast, VCSELs can be grownin an array of any size, shape, and quantity on a single die, tested onthe die, and then diced into individual chip “tiles” which can then beassembled together to provide a seamless (100% fill factor) linear arrayof arbitrary size. Semiconductor lasers comprise layers of semiconductormaterial grown on top of each other on a substrate (the “epi”). ForVCSELs and edge-emitters, this growth is typically done in amolecular-beam-epitaxy (MBE) or metal-organic-chemical-vapor-deposition(MOCVD) growth reactor. The grown wafer is then processed accordingly toproduce individual devices.

VCSELs, however, are semiconductor lasers, more specifically laserdiodes with a monolithic laser resonator, where the emitted light leavesthe device in a direction perpendicular to the chip surface. Theresonator (cavity) is realized with two semiconductor Bragg mirrors(→distributed Bragg reflector lasers). Between those, there is an activeregion (gain structure) with (typically) several quantum wells and atotal thickness of only a few micrometers. In most cases, the activeregion is electrically pumped with a few tens of milliwatts andgenerates an output power in the range from 0.5-5.0 mW, or higher powersfor multimode devices. The current is often applied through a ringelectrode, through which the output beam can be extracted, and thecurrent is confined to the region of the resonator mode usingelectrically conductive (doped) mirror layers with isolating materialaround them. In a VCSEL, the active layer is sandwiched between twohighly reflective mirrors (distributed Bragg reflectors, or DBRs) madeup of several quarter-wavelength thick layers of semiconductors ofalternating high and low refractive index. The reflectivity of thesemirrors is typically in the range 99.5-99.9%. As a result, the lightoscillates perpendicular to the layers and escapes through the top (orbottom) of the device. Current and/or optical confinement is typicallyachieved through either selective oxidation of an Aluminum-rich layer,ion-implantation, or even both for certain applications. The VCSELs canbe designed for “top-emission” (at the epi/air interface) or“bottom-emission” (through the transparent substrate) in cases where“junction-down” soldering is required for more efficient heat-sinkingfor example.

In contrast, edge-emitters are made up of cleaved bars diced from thewafers. Because of the high index of refraction contrast between air andthe semiconductor material, the two cleaved facets act as mirrors.Hence, in the case of an edge-emitter, the light oscillates parallel tothe layers and escapes side-ways. This simple structural differencebetween the VCSEL and the edge-emitter has important implications.

Since VCSELs are grown, processed and tested while still in the waferform, there is significant economy of scale resulting from the abilityto conduct parallel device processing, whereby equipment utilization andyields are maximized and set up times and labor content are minimized.In the case of a VCSEL (see FIG. 1), the mirrors and active region aresequentially stacked along the Y axis during epitaxial growth. The VCSELwafer then goes through etching and metallization steps to form theelectrical contacts. At this point the wafer goes to test whereindividual laser devices are characterized on a pass-fail basis.Finally, the wafer is diced and the lasers are binned for eitherhigher-level assembly (typically >95%) or scrap (typically <5%).

In a simple Fabry-Perot edge-emitter, the growth process also occursalong the Y axis, but only to create the active region as mirrorcoatings are later applied along the Z axis. After epitaxial growth, thewafer goes through the metallization step and is subsequently cleavedalong the X axis, forming a series of wafer strips. The wafer strips arethen stacked and mounted into a coating fixture. The Z axis edges of thewafer strips are then coated to form the device mirrors. This coating isa critical processing step for edge emitters, as any coatingimperfection will result in early and catastrophic failure of thedevices due to catastrophic-optical-damage (COD). After this coatingstep, the wafer strips are diced to form discrete laser chips, which arethen mounted onto carriers. Finally, the laser devices go into test.

It is also important to understand that VCSELs consume less material: inthe case of a 3″ wafer, a laser manufacturer can build about 15,000VCSEL devices or approximately 4,000 edge-emitters of similar powerlevels. In addition to these advantages, VCSEL also demonstrateexcellent dynamic performances such as low threshold currents (a fewmicro-amps), low noise operation and high-speed digital modulation (10Gb/s). Furthermore, although VCSELs have been confined to low-powerapplications—a few milli-Watts at most—they have the inherent potentialof producing very high powers by processing large 2-D arrays. A 2-DVCSEL array with several thousand emitters can emit several hundredwatts of total optical power. In contrast, edge-emitters cannot beprocessed in 2-D arrays.

An important practical advantage of VCSELs, as compared withedge-emitting semiconductor lasers, is that they can be tested andcharacterized directly after growth, i.e. before the wafer is cleaved.This makes it possible to identify quality problems early on, and toreact immediately. Furthermore, it is possible to combine a VCSEL waferwith an array of optical elements (e.g. collimation lenses) and thendice this composite wafer instead of mounting the optical elementsindividually for every VCSEL. This allows for cheap mass production oflaser products. Feature of VCSELs is the long lifetime, as there is nofacet which can be damaged by high optical intensities.

Unlike conventional semiconductor lasers, which emit from the side,VCSELs emit from the surface, which allows on-wafer testing arrays ofdevices. This provides many advantages. The lasing wavelength in a VCSELis very stable, since it is fixed by the short (1˜1.5-wavelength thick)Fabry-Perot cavity. Contrary to edge-emitters, VCSELs can only operatein a single longitudinal mode. Growth technology has improved such thatVCSEL 3″ wafers are produced with less then a 2 nm standard deviationfor the cavity wavelength. This allows for the fabrication of VCSEL 2-Darrays with little wavelength variation between the elements of thearray (<1 nm full-width half-maximum spectral width). By contrast,edge-emitter bar-stacks suffer from significant wavelength variationsfrom bar to bar since there is no intrinsic mechanism to stabilize thewavelength, resulting in a wide spectral width (3-5 nm FWHM). Theemission wavelength in VCSELs is ˜5 times less sensitive to temperaturevariations than in edge-emitters. The reason is that in VCSELs, thelasing wavelength is defined by the optical thickness of the singlelongitudinal-mode-cavity and that the temperature dependence of thisoptical thickness is minimal (the refractive index and physicalthickness of the cavity have a weak dependence on temperature). On theother hand, the lasing wavelength in edge-emitters is defined by thepeak-gain wavelength, which has a much stronger dependence ontemperature. As a consequence, the spectral line-width for high-powerarrays (where heating and temperature gradients can be significant) ismuch narrower in VCSEL arrays than in edge-emitter-arrays (bar-stacks).Also, over a 20 degree Celsius change in temperature, the emissionwavelength in a VCSEL will vary by less than 1.4 nm (compared to ˜7 nmfor edge-emitters).

Additional advantages provided by utilizing VCSEL configurations overedge-emitters include that because VCSELs can operate reliably attemperatures up to 80 degrees Celsius, they can be operated withoutrefrigeration. Thus, the cooling system becomes very small, rugged andportable with this approach. Edge emitters deliver a maximum of about500 W/cm2 because of the gap between bar to bar which has to bemaintained for coolant flow, while VCSELs are delivering ˜1200 W/cm2 nowand can deliver 2-4 kW/cm2 in the near future. VCSELs emit a circularbeam. Through proper cavity design VCSELs can also emit in a singletransverse mode (circular Gaussian). This simple beam structure greatlyreduces the complexity and cost of coupling/beam-shaping optics(compared to edge-emitters) and increases the coupling efficiency to thefiber or pumped medium. This has been a key selling point for the VCSELtechnology in low-power markets. Because VCSELs are not subject tocatastrophic optical damage (COD), their reliability is much higher thanfor edge-emitters. Typical FIT values (failures in one billiondevice-hours) for VCSELs are less than 10. VCSEL do not have the failuremode of traditional edge emitting diodes such as line defects.

Manufacturability of VCSELs has been a key selling point for thistechnology. Because of complex manufacturing processes and reliabilityissue related to COD (catastrophic optical damage), edge-emitters have alow yield (edge-emitter 980 nm pump chip manufacturers typically onlyget ˜500 chips out of a 2″ wafer). On the other hand, yields for VCSELsexceed 90% (corresponds to ˜5000 high-power chips from a 2″ wafer). Infact, because of its planar attributes, VCSEL manufacturing is identicalto standard IC Silicon processing. Enables the use of traditionalsemiconductor manufacturing equipment to keep fabrication costs down.This also allows for good integration ability, as VCSEL are compatiblewith detectors and other circuitry. VCSELs can also be tested and burnedin while still in wafer form, which increases the manufacturing yieldand lowers cost. For high-power applications, a key advantage of VCSELsis that they can be directly processed into monolithic 2-D arrays,whereas this is not possible for edge emitters (only 1-D monolithicarrays are possible). In addition, a complex and thermally inefficientmounting scheme is required to mount edge-emitter bars in stacks.Mounting of large high-power VCSEL 2-D arrays in a “junction-down”configuration is straightforward (similar to micro-processor packaging),making the heat-removal process very efficient, as the heat has totraverse only a few microns of AlGaAs material. Record thermalimpedances of <0.16K/W have been demonstrated for 5 mm×5 mm 2-D VCSELarrays. With the simple processing and heat-sinking technology, itbecomes much easier to package 2-D VCSEL arrays than an equivalentedge-emitter bar-stack. The established existing silicon industryheat-sinking technology can be used for heat removal for very high powerarrays. This will significantly reduce the cost of the high-powermodule. Currently, cost of the laser bars is the dominant cost for theDPSS lasers.

The most common emission wavelengths of VCSELs are in the range of750-980 nm (often around 850 nm), as obtained with the GaAs/AlGaAsmaterial system. However, longer wavelengths of e.g. 1.3, 1.55 or evenbeyond 2 μm can be obtained with dilute nitrides (GaInNAs quantum wellson GaAs) and from devices based on indium phosphide (InAlGaAsP on InP).The use of these wavelengths can be employed to thermal cure, sinter,melt, or cause photo curing with appropriate photoinitiators thatproduce free radicals in those wavelengths. Harmonic Generation viacrystal nonlinear processes can create other shorter wavelengths thatotherwise may not be produced directly from the semiconductor. Usingnonlinear crystals such as KTP, MgO, PPLN, etc—conversion isproportional to intensity and the crystal structure allows, via varyingperiodicity of phase within crystal, tuning of the optical resonance ofthe crystal to achieve different output wavelengths. For a given VCSEL,simply changing the nonlinear crystal can change the output wavelength.For example, an 808 nm source could be doubled into a 404 nm output, ortripled into a 269 nm output, etc., simply by changing the crystalmaterial, or a 976 nm source could be doubled to 488 nm. Othersolid-state direct-emissive sources such as microLED are limited inpower and beam quality or coherent output capability. MicroLEDstypically will have a lambertian intensity distribution from theemitting surfaces, which need collecting and focusing options with highNA to gather light and direct a small spot into the system. VCSEL lasersrepresent a much closer realization to a perfect point source and can beefficiently collimated and focused to a small spot size withoutrequiring expensive (high-NA/high collection) optical systems.

In addition to the high beam quality of low-power VCSELs, an importantaspect is the low beam divergence, compared with that of edge-emittinglaser diodes, and the symmetric beam profile. This makes it easy tocollimate the output beam with a simple lens, which does not have tohave a very high numerical aperture. Due to the fact that the VCSELsources are much closer to an ideal light source, relatively inexpensiveoptics (microlens arrays or equivalent) with equivalent center-to-centerpitch placed over top of the VCSEL emitter die can be used to create theproper focused spot.

Specific embodiments utilizing VCSEL configurations integrated into 3Dprinting systems will now be described. Each of these light sources canbe utilized and integrated into 3D printing systems, including any ofthe 3D printing systems disclosed herein and can replace the lightsources disclosed above. FIGS. 23A-B show a chip-level sectional view ofexample configurations between chip-level the VCSEL light sources andthe control drivers. FIGS. 23A and 23B show a VCSEL chip 1000 comprisingone or more VCSEL emitters 1002 (three shown) on a common substrate1004. A control driver 1006 is external to but communicatively coupledto the VSCEL chip 1000. Both the VSCEL chip 1000 and the control driver1006 are bonded to a common heat spreading substrate 1008. In both FIG.23A and FIG. 23B, the control driver 1006 is external to, and not indirect physical contact with, the VCSEL chip 1000. In FIG. 23A, thecontrol driver 1006 is electrically communicatively coupled to both acontact 1010 by one or more wire bonds 1020 (two shown). In FIG. 23B,the control driver 1006 is electrically communicatively coupled to botha contact 1010 by one or more conductive bridges 1030 (one shown).Specific driver configurations are described in greater detail furtherherein.

FIGS. 24A-24B show a chip-level sectional view of example configurationsbetween the VCSEL light sources and the control drivers. FIGS. 24A and24B show a VCSEL chip 1100 comprising one or more VCSEL emitters 1102(three shown) on a common substrate 1104. A control driver 1106 iscommunicatively coupled to the VSCEL chip 1100. Both the VSCEL chip1100. The VCSEL chips 1100 are in thermal communication with a heatspreading substrate 1108. In contrast with FIG. 23A and FIG. 23B, thecontrol driver 2 1106 are in direct physical contact with the VCSELchips 1100. In FIG. 24A, the control driver 1006 is stacked with theVCSEL chip 1100. In FIG. 24B, the control driver 1106 is integrated intothe substrate 1104. The integrated monolithic driver 1106 of FIG. 24Bprovided a cost-effective integrated package.

Using VCSEL technology, a driver can be either external (e.g. CMOS ASIC)or can be integrated directly into the GaAs wafer for a completelymonolithic structure. The latter offers benefits in terms of integrationflexibility, reduced cost, fewer interconnects, increased reliability.Temperature sensing junctions could also be integrated into the die toallow precise feedback and control of the emitter temperature—forprecise wavelength tuning/stabilization. This has applications forensuring efficient second harmonic generation (SHG) processes. Otherbenefits of temp sensing junctions placed sparsely along the arrayinclude the ability to closely monitor and control emitters. Ability tooverdrive specific emitters or emitter groups without negativelyaffecting the chip as a whole.

In some embodiments, each of the numerous emitters on the VCSEL chip isaddressed individually channel-for-channel through direct connection toa configurable Complementary metal-oxide-semiconductor (CMOS)application specific integrated circuit (ASIC) driver chip functioningas a specialized n-channel constant-current input/output (I/O) expander,which is controlled via serial low-voltage differential signaling (LVDS)from the main system field-programmable gate array (FPGA). The CMOSdriver chip provides the main FPGA an interface to control each channelwith 10-bit control of current and 10-bit control of the duration ofthat current, yielding a total of 20 bits of exposure control perchannel.

FIG. 25 shows a print head 1200, with one or more VCELs 1202 arrangedthereon (a plurality in array shown). In the embodiment shown in FIG.25, the VSCELs are arranged in a staggered array. The print head 1200can comprise similar structure, materials and configuration as any ofthe materials dispensers 180, 184 described earlier herein. The printhead 1200 can further comprise a VSCEL substrate 1204, which can besimilar to the substrates 1004, 1104 described above with reference toFIGS. 23-24. The print head 1200 can further comprise VSCEL drivers1206, similar to the VSCEL drivers 1006, 1106 described above withreference to FIGS. 23-24, which can be near and communicativelyconnected to the VSCELS 1202. The print head 1200 can also comprisememory, with the embodiment shown comprising driver random access memory(RAM) 1208 and flash memory 1210. The print head 1200 can also comprisean FPGA 1212 to provide further control over the VCSEL functions. Thememory and processing components of the print head 1200 can beintegrated into a print head printed circuit board (PCB).

VCSEL chips in an array may be staged from one another, for example, asshown in FIG. 25, and/or individual VCSEL emitters within the chips canbe staggered from one another. The stagger of the VCSEL chips andemitters can be designed and optimized for factors such as, designedoptics, emitter size and energy, fill factor, optical system, spot size,cooling, tiling strategies, overcoming dead or inactive emitters.Alternatively, the VCSEL chips can be configured in a non-staggered orlinear array.

The print head 1200 in FIG. 25 can also comprise cooling elements, whichare useful to provide cooling when a high-powered VSCEL array isutilized as a curing system. Some cooling elements the print head 1200can comprise include a thermoelectric cooler (TEC) 1214, for example, aPeltier cooler, and thermal conduction modules 1216, which can sensetemperature changes and electrically communicate with driverscontrolling the TEC 1214. In the embodiment shown in FIG. 25, heat thatis generated in the VSCEL emitter zone can be drawn through the VSCELsubstrate 1204 and into a heatsinking mechanism. Some exampleheatsinking mechanisms include, for example, microchannel plates,peltier coolers, air heat exchanger, or other heatsinking methods. Asdiscussed above, the TEC 1214 is the heatsinking mechanism utilized inthe embodiment of FIG. 25.

Heat loads on the print head 1200 are time-varying and print-specific.For example, a single emitter or 1,000 emitters could be active at anygiven moment to replicate a portion of data in physically cured polymer.Precise knowledge of local temperature allows optimization of printspeed for a given object. The thermal management system is able torespond to changing heat loads on a timescale sufficient to ensure thejunction temperature of the VCSEL chips 1202 stays within a narrowtemperature window during operation to ensure stable wavelength andefficient SHG. The CMOS ASIC drivers have a more relaxed thermaloperating window, requiring the junction temperature to remain below 125C.

Utilizing a TEC to reduce the time constant of the cooling feedback loopallows the system to respond much faster to varying heat loadselectrically and maintain a constant chip temperature. A general modelof the system can be constructed, and used at run-time in conjunctionwith queued array data and a heat transfer function of the VCSEL emitterto feed-forward thermal control into the closed-loop system and helpachieve tight response times.

This means that the system is not as reliant on the coolant loop tomaintain the proper temperature—only to remove heat from the system inwhatever quantity it is present at the hot end of the TEC. In order tominimize thermal resistance across the system and maximize thermalcontrol loop response times, the number of thermal interfaces betweenemitter and ultimate heat removal is kept to an absolute minimum. Eachthermal interface is joined with high-quality thermal paste or epoxy,which in some embodiments, comprises a layer that is 0.001″ or thinner.A further benefit of the TEC-based system is the ability to pre-heat theVCSEL chips to 75 degrees Celsius for optimally-efficient SHG when firststarting a print. Tight real-time control over heat flow through thesystem—VCSEL junction temperature should ideally be controlled to withinunder 5 degrees Kelvin. Care must be taken with placement of thetemperature sensors to ensure accurate feedback. In some embodiments,temperature sensing junctions should be integrated directly into theVCSEL die for maximally-accurate feedback.

FIG. 26 shows the print head 1200 of FIG. 25 integrated into a rotatableprint head platform structure 1300. The rotatable print head platformstructure 1300 can comprise a print head main printed circuit board(PCB) 1302, which is coupled to the print head 1200, a mainrandom-access memory 1304, a microprocessor 1306, a secondary controller1308 (for example, a Flexray® controller), and a TEC controller PCB 1310coupled to one or more TEC controllers 1312. Each of these structurescan be mounted to a fixed base 1314, which can be configured with theabove features to form a rotatable configuration utilizing a rotationmotor 1316 and a rotary table 1318.

The rotation motor 1316 and the rotary table 1318 can comprise arotational configuration similar to that of the build platform 16herein. The resulting rotating VCSEL array provides necessary energydensity at simultaneous point on a radial in a rotary system to induceclose to instantaneous solidification of material, allowing for fasterprinting and the ability to solidify a greater range of materials withhigher energy levels to induce a phase change. The print head 1200 onthe separate rotary scanning system exposes larger areas, or increasesthe print speed of the system without increasing the rotational speed ofthe rotating build plate (described above). This allows the speed ofrotation of the build plate to be optimized for adhesion removal,material distribution, or other factors without sacrificing print speed.This also allows for greater energy VCSELS to be used where if highenough energies were attained beyond the optimized build plate speedthis energy can now be utilized through rotational scanning. A rotatinglight source also removes the need to have multiple fixed positionpolarly arranged arrays, which reduces cost of the machine and increasethe number of possible cure zone areas as the position of the rotatinglight source is now configurable. Allows for printing in continuous andsemi-continuous motion where some materials may have a longer curereaction necessary for the build plate to be stationary before it moves.

It is important to note that while the present disclosure focuses on arotating build plate and a rotating radiation source in the form of theVCSEL array, the rotating radiation sources disclosed here can beutilized in 3D printing systems without a rotating build platform, forexample, stationary build plates. Furthermore, the rotating radiationsource and the rotating build plate can be controlled separately ortogether and can comprise their own associated drivers. In someembodiments, the rotating radiation source and the rotating build platecan be configured to have different characteristics including rotationaland angle characteristics and/or different speeds.

A rotating light source also opens up the option for various cure zonegeometries as shapes to be used rather than simple pie shapes orradials. Individual islands or different vats with different cure zonegeometries optimized for different materials with consideration of fluiddynamics based on viscosity or particle size, adhesion characteristics,Allows for greater variety of vat segmentation for multiple materials(this compares to fixed VCSEL or a linear or rectilinear light sourcelike laser with single galvo or projection system).

FIG. 27 shows a side profile view of the rotatable print head platformstructure 1300 of FIG. 27, which can comprise the print head 1200, thefixed base 1314, the rotation motor 1316, the rotary table 1318, amultichannel slip ring 1402, and a rotation bearing 1404. As can be seenin FIG. 27, The rotation motor 1316, is configured to impart rotarymotion to the rotary table 1318 relative to the fixed based 1314. Therotary table #1318 is rotatably affixed to fixed base 1314 through therotation bearing 1404. Power and signals are transferred to rotatableprint head platform structure 1300 through the multichannel slip 1402.

In some embodiments rotatable print head platform structure 1300 furthercomprises a fluid delivery system for liquid cooling of the thermalconduction modules of the print head 1200, in which a cooling fluid, forexample, water or any known cooling fluid, is conducted through arotational fluid coupling 1406, for example, from a fluid coolingreservoir 1407. In some embodiments, such as the embodiment shown inFIG. 27, the heat sinking system utilized is not only a TEC, but isinstead a hybrid thermoelectric/fluid cooling system. In this hybridsystem, the heat produced by a VCSEL array is spread out via its heatspreader submount to the cold side of a TEC module heat pump. Geometryof the VCSEL heat spreader submount can be optimized using FEAtechniques to ensure optimal heat throughput and even temperatureprofiles. One or more thermoelectrically-cooled submount modules arepositioned with their hot sides on a larger water-cooled base blockaccording to optical and electronic design considerations. Rotationalfluid coupling allows for the liquid cooling of the print head while itrotates. Cooling fluid can be pumped into the outer portion of the printhead 1200 to allow for the coldest fluid to be introduced to the outeremitters, which will be generating more heat then the inner emitters.

Many different VCSEL array configurations are possible incorporatingfeatures of the present invention, both integrated into and separatefrom, a print head. FIG. shows a light engine 1500, featuring an 8-zonelight engine structure. The light engine 1500 comprises arms 1502 (8shown), upon which VCSEL arrays 1504 are arranged. The light engine 1500can be configured with the same cooling features and/or the rotationalfeatures as the print head 1200 described above.

Various overall operational control schemes can be utilized withembodiments of VCSEL light sources incorporating features of the presentinvention. FIG. 29 shows an example operational configuration 1600,wherein a system master controller 1602, for example, a computing devicesuch as a memory in communication with a processor, is configured tosend commands to various subsystems and controllers and to receive userand machine inputs and deliver print specific data to print headsubsystem. In some embodiments, the system master controller 1602 iscommunicatively coupled to the other subsystems and controllers via ahigh speed serial bus 1603. A load/unload subsystem 1604 is configuredto handle loading and unloading of the build plate to and from themachine.

A print head subsystem 1606 is configured to receives print-related datafrom system master controller, process this information to produceindividual emitter pulses, to sense thermal condition of the array andfeed info back to print head micro controller or system mastercontroller. This information is processed and used to regulate arraytemp. The print head subsystem 1606 is configured to receive print datafrom system master controller, store print data in local memory, andsend data to VCSEL drivers (where the VCSEL drivers covert this datainto pulse commands for the individually addressable emitters whichsolidifies materials associated with desired 3d object). The print headsubsystem 1606 also utilizes thermal sensors and relays information toprint head driver FPGA and on to printhead subsystem microcontroller.This information can be processed at a microcontroller or passed tosystem master controller to regulate print head operations. Regulationis achieved through the adjustment of voltages of the TAC coolers by theTAC cooler controllers, which receive the adjustment commands from theFPGA, print head microcontroller or system maters controller. In someembodiments, a secondary controller, similar to secondary controller1308, such as a Flex Ray® controller, sends and receives information toand from the system master controller.

A print head motion controller 1608 is configured to receive print leveldata for controlling the rotatory and linear advancement of the buildplate, receive information from position sensors to monitor build platetheta and z-access distance, and to receive torque data. A build platesubsystem 1610 is configured to provide control to the build plate. Aresin vat controller 1612 is configured to control and monitor theprint-materials storage portions of the device.

Although the present invention has been described in detail withreference to certain preferred configurations thereof, other versionsare possible. Embodiments of the present invention can comprise anycombination of compatible features shown in the various figures, andthese embodiments should not be limited to those expressly illustratedand discussed. Therefore, the spirit and scope of the invention shouldnot be limited to the versions described above.

The foregoing is intended to cover all modifications and alternativeconstructions falling within the spirit and scope of the invention asexpressed in the appended claims, wherein no portion of the disclosureis intended, expressly or implicitly, to be dedicated to the publicdomain if not set forth in any claims.

We claim:
 1. A device for three-dimensional (3D) printing of structuresin a vertical orientation, comprising: a build platform moveablevertically and configured to rotate around a central axis; a materialdispenser with a flowable build material in said material dispenser,said material dispenser being positioned for controlled delivery of theflowable build material to an exposure zone of a surface of the buildplatform or a 3D structure being formed; and one or more laser diodechips on or adjacent said material dispenser, said laser diode chipspositioned to deliver radiation to solidify the flowable build materialdelivered in a controlled manner to the build platform or the 3Dstructure being formed, when said build material is located in or on theexposure zone.
 2. The device of claim 1, wherein said material dispensercomprises a print head.
 3. The device of claim 1, wherein said one ormore laser diode chips are vertical-cavity surface-emitting laser(VCSEL) chips comprising an array of VCSEL chips.
 4. The device of claim3, wherein said array of VCSEL chips is in a staggered orientation. 5.The device of claim 3, wherein at least one of said one or more VCSELchips is communicatively connected to a VCSEL driver configured tocontrol said at least one of said one or more VCSEL chips.
 6. The deviceof claim 5, wherein said VCSEL driver and said at least one of said oneor more VCSEL chips share a common substrate.
 7. The device of claim 6,wherein said VCSEL driver is integral with said common substrate.
 8. Thedevice of claim 3, further comprising a thermoelectric cooler (TEC)configured to provide cooling to said one or more VCSELs.
 9. The deviceof claim 6, further comprising a fluid-based cooler system comprising arotational fluid coupling configured to cool said one or more VCSELs.10. The device of claim 1, wherein the central axis is configured to bemoveable in a controlled manner within a defined space within aconstruction frame.
 11. A device for three-dimensional (3D) printing ofstructures in a vertical orientation, comprising: a build platformmoveable vertically and configured to rotate around a central axis, saidcentral axis fixed or configured for controlled movement in an areawithin a construction frame, a material dispenser with a flowable buildmaterial in said material dispenser, said material dispenser beingpositioned to deliver the flowable build material in a controlled manneronto the build platform in or on a construction area; and one or moreLEDs or semiconductor lasers chips mounted in an array on or adjacentsaid material dispenser, said semiconductor lasers chips positioned todeliver radiation to solidify the flowable build material located on thebuild platform or on a 3D structure being formed in the constructionarea within an exposure zone of the build platform or on at leastpartially solidified build material previously deposited on the buildplatform.
 12. The device of claim 11, wherein said material dispensercomprises a print head.
 13. The device of claim 11, wherein said one ormore semiconductor lasers chips are laser diode chips or vertical-cavitysurface-emitting laser (VCSEL) chips, the one or more semiconductorlasers chips arranged as an array of chips.
 14. The device of claim 13,wherein the VCSELs in the array are selected from the group consistingof visible light, UV, IR or near IR radiation emitting VCSELs.
 15. Thedevice of claim 13, wherein the VCSELs in the array emit radiation atselected frequencies from 280-480 nm and/or 650-1500 nm and the arraycan comprise one or more VCSELs delivering different emissionfrequencies.
 16. The device of claim 13, wherein said VCSEL chips are ina staggered orientation in the array.
 17. The device of claim 13,wherein at least one of said one or more VCSEL chips is communicativelyconnected to a VCSEL driver configured to control said at least one ofsaid one or more VCSEL chips.
 18. The device of claim 17, wherein saidVCSEL driver and said at least one of said one or more VCSEL chips sharea common support surface.
 19. The device of claim 11, wherein saidsemiconductor lasers chips are mounted on a second table within theconstruction frame, said second table fixed in position or configured torotate in relationship to a non-rotational or rotational build platform.20. The device of claim 11, wherein said material dispenser is on arotary table configured to rotate in relation to the build platform. 21.The device of claim 20, further comprising a thermoelectric cooler (TEC)configured to provide cooling to said one or more VCSELs.
 22. The deviceof claim 21, further comprising a fluid-based cooler system comprising arotational fluid coupling configured to cool said one or more VCSELs.23. A device for three-dimensional (3D) printing of structures in avertical orientation, comprising: a construction frame; one or morematerial dispensers with flowable build material in said materialdispensers; a construction area in a space defined by the constructionframe, and a separate build platform, the build platform positionedhorizontally within said construction frame and configured for buildinga solidified 3D structure on the build platform and in the constructionarea, said build platform moveable vertically within and configured torotate within said construction frame while the flowable build materialis being delivered to the build platform or onto the 3D structure beingformed; the material dispenser being positioned to deliver the flowablematerial onto the build platform or in the construction area; and one ormore vertical-cavity surface-emitting laser (VCSEL) chips positioned todeliver radiation to selectively expose and solidify the flowable buildmaterial located on the build plate or on the 3D structure being formedin a zone for curing; said build platform configured to receive andretain the build material delivered to said build platform or into theconstruction area as the exposed flowable build material solidifies andto move vertically and to rotate within the construction frame.
 24. Thedevice of claim 23, wherein the one or more VCSELs are mounted to afirst plate configured to rotate in relationship to the build platform.25. The device of claim 23, wherein the one or more material dispensersare mounted to the first plate or a second plate configured to rotate inrelationship to the build platform.
 26. The device of claim 23, whereinsaid material dispenser is on a rotary table configured to rotate inrelation to the build platform.
 27. A device for three-dimensional (3D)printing of structures in a vertical orientation, comprising: a buildplate, one or more material dispensers and solidification deliverysystems, the build plate, one or more material dispensers andsolidification delivery systems moveable vertically and configured torotate around a central axis, said central axis fixed or configured forcontrolled movement within a construction frame, a flowable buildmaterial in said one or more material dispensers, said materialdispensers being positioned to deliver the flowable build material in acontrolled manner onto a surface on the build plate or in a constructionarea for selective exposure by a solidifying medium; and one or moresolidification delivery systems mounted on or adjacent said materialdispenser, said solidification delivery systems positioned to deliverthe solidifying medium to the flowable build material delivered to thebuild platform or into the construction area in a zone for curing theflowable build material.
 28. The device of claim 27, wherein thesolidifying means delivered by the solidification delivery systemscomprised a radiation source, heating or cooling means, or a chemicalreactant.
 29. The device of claim 28, wherein the radiation sourcecomprises a focused light source providing energy at a controlledfrequency.
 30. The device of claim 27, wherein the solidificationdelivery system is positioned adjacent to the construction area and toselectively solidified the build material on the build plate or in theconstruction area positioned above or below the solidification deliverysystem.